1. Field of the Invention
The invention relates generally to the fields of autoimmunity and inflammatory bowel disease and more specifically to the diagnosis and treatment of a clinical subtype of ulcerative colitis.
2. Background Information
Inflammatory bowel disease (IBD) is the collective term used to describe two gastrointestinal disorders of unknown etiology: Crohn's disease (CD) and ulcerative colitis (UC). The course and prognosis of ulcerative colitis, which occurs world-wide and is reported to afflict as many as two million people, varies widely. Onset of ulcerative colitis is predominantly in young adulthood with diarrhea, abdominal pain, and fever the three most common presenting symptoms. The diarrhea may range from mild to severe and often is accompanied by bleeding. Anemia and weight loss are additional common signs of UC. Ten percent to fifteen percent of all patients with inflammatory bowel diseases such as UC will require surgery over a ten year period. In addition, patients with UC are at increased risk for the development of intestinal cancer. Reports of an increasing occurrence of psychological problems, including anxiety and depression, are perhaps not surprising symptoms of what is often a debilitating disease that strikes people in the prime of life.
Unfortunately, the available therapies for ulcerative colitis are few, and both diagnosis and treatment have been hampered by a lack of knowledge regarding the etiology of the disease. What is clear, however, is that the pathogenesis of ulcerative colitis involves immune-mediated damage to the intestinal mucosa. Autoantibodies, specifically antibodies against cytoplasmic components of neutrophils (pANCA), have been reported in 68-80% of patients with ulcerative colitis, further supporting a role for immune dysregulation in this disease. However, the UC pANCA target antigen, which would be useful in diagnosing and treating the large population of UC patients that have pANCA autoantibodies has, to date, escaped identification. Thus, there is a need for methods of diagnosing and treating ulcerative colitis using the ulcerative colitis pANCA target antigen. The present invention satisfies this need and provides related advantages as well.